fix: remove unused import and trailing blank line in test_token_usage_utils

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: Prachig-Microsoft

src/ContentProcessor/tests/unit/libs/test_token_usage_utils.py

@@ -5,7 +5,7 @@
 
 from __future__ import annotations
 
-from unittest.mock import MagicMock, patch
+from unittest.mock import MagicMock
 
 from libs.llm_token_telemetry import (
     TokenUsage,
@@ -369,4 +369,3 @@ def test_scope_accumulates_multiple_adds(self):
         assert scope.usage.input_tokens == 300
         assert scope.usage.output_tokens == 130
         assert scope.usage.total_tokens == 430
-